Press Forming

The stamp forming process for thermoplastic composites is well suited for automated high volume production. It is for example applied to manufacture large series of clips and brackets used in aeronautical structures. Application of the technology is, however, not straightforward as it largely relies on specific (and often inaccessible) knowhow and requires relatively large investment costs.

Background/Introduction

Process window optimization and tool design are critical steps in the development of a new thermoplastic composite part, especially when stamp forming is used. For example, mold cavity design is not straight-forward when complex three-dimensional shells are manufactured. Fiber reorientation due to double curvature, followed by local thickening of the material, needs to be predicted to avoid a non-uniform pressure distribution. The occurrence of defects such as wrinkles is ideally prevented by i.e. a well-chosen blank holder design, but if unavoidable, the effect on the part performance should be known.

Approach

The basic principles behind the forming behavior of thermoplastic composites are identified and translated to predictive (numerical) models. The research includes further work on the characterization and description of the behavior of thermoplastic composites in melt conditions, extending previous work on continuous fiber reinforced thermoplastics to discontinuously reinforced polymers and hybrid combinations of these materials. Subsequently, the material performance is captured as a function of the process parameters, which allows for both the consistent design of a new part as well as the optimization of an existing process chain.

TPRC, the ThermoPlastic composites Research Center in the Netherlands, is an open innovation, research- and development center that aims for thermoplastic composites for a broad range of end use markets.